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G'day all,
I need to do some welding soon on the jet boat and would appreciate any tips from those who know.
I have been stick welding for years on steel , even got a few jobs under the belt which were underwater.

I have done a little tig work on Stainless before (very badly)

I have not quite got my steel welds with the mig as good as what I can do with a stick, but Alloy is supposed to be a whole new ball game.

This weekend I am into it with a new spool of wire and a new bottle of gas .

Gracias.

Cleaness is essential with aluminium, also a new line as the aluminium wire will flow better and not pick up the steel in the liner used for steel wire. This what i have picked up so far off mates who do it but still haven't got aluminium welding to were i want it.

haha, stick welding well is very easy - infact did my first using 2xcar batteries, and it was good - probably because with stick, an over abundance of current ensures a good weld.
Mig, your starting to be a bit more precise with the current and the feed, probably because
your welding thinner steels, and you don't want to blow the job apart - so here practice and experience is required.
I gather your going to try the Al wire and Argon gas with your mig? hope you have better luck than I, but supposedly it can do a pasable job, not sure how strong.
I've done stainless welding with the mig tho, and it worked out ok, tho couldv'e been cleaner.
Tig is the thing to use, but those machines cost way more, need more juice and are bigger..........(ie i need more room)

Yep, Fred
Argon and Alloy wire through a brand new line and nozzle.

Cross your fingers for me, I have heaps of scraps to try on first thankfully.

BRUMBERTY wrote: Argon and Alloy wire through a brand new line and nozzle.

That may indeed be the key, I was advised likewise, but thought if just giving it a go,
I'll do with the current setup, but result was basically woefull. If you report a satisfactory result:p I'll get the new line/nozzle too for next time.

I struck it lucky, the Mig's owner got a line for each type of wire,
he has never been brave enough to try alloy, thus its still new.

I Bought a bottle of gas and a nice bottle of red.
We are learning together.

Keep the motion constant and quicker than you would with steel.

Thanks, uphill or downhill if you got to choose, Subi Wan?

If you have not played with alloy before and have to weld it up or down i would choose down and drag the torch. Alloy has only a slight change to the surface look before too much heat is applied and you get a hole or a molten pool.

and if your mig machine is only a push set up (ie, only one roller feeding the wire close to the spool) keep your work lead as straight as possible, use 1.2mm wire and about 18 ltrs per minute of gas... you can weld up or down on ali, but takes a fair bit of practice and knowledge of material/machine etc etc etc...

ideally, u should use a push/pull hand piece (one roller near the spool and one roller in the hand piece) this will make life so much easier and you can use 0.9mm...

are you welding plate or extrusion??? ie round bar type stuff or plate???

if your welding round bar, clean about 20mm clear around the joint you want to weld..

hope all the info helps

oh, and you have to change the roller in the feeder... steel wire uses a V groove where as ali needs a U groove, if u use the ali with a V groove, it will pinch the wire and birds nest

Cheers Jay, I was hoping you would pipe up at some stage.
I am nervous.

I am joining-

Extrusions to extrusions first.
Box section to box section for the ribbing and stringers

C section (gunwail) to box to keel for the ribs too.

Old plate 2.5mm (transom) to new plate 6mm (transom)
to framework (20mm box)

Filling holes (lots and lots and lots) which old screws have been
(32 and counting).
Mainly in the sides (3mm plate)

And then I can get onto fixing the splits!!

This old girl has seen more big waves than all of us, a heavy work load as a Crayfish boats tender has left a lot of scarring and its history shows, a great starting point for its new life as "That loud jetboat".